The incidence of obesity in the United States is significantly increasing causing an associated increase in obesity-related health problems. Because of this trend, efforts to control obesity are gaining the increased attention of both the medical community and the general public. However, while there may be a considerable number of individuals that are markedly overweight, a fraction of these individuals are currently eligible for surgery to reconstruct their gastrointestinal (GI.) tract in order to control their weight. These GI procedures are reserved for the severely obese because of the significant complications associated with the surgery. Because these procedures often involve invasive surgery, the recuperation time is significant not to mention the possibility of complications which include the risk of death. It is estimated that without GI reconstruction, eligible patients face an annual mortality as high as 30%-50%. Obviously such a high risk of death justifies the use of these surgical procedures. It is contemplated that less invasive procedures would be better suited for the severely obese as well as those moderately or less obese.
FIG. 1A is an illustration of the digestive system. The digestive tract is a disassembly line in which food breaks down to become less and less complex so that nutrients become available to the body. As the food passes through the digestive tract, it mixes with other fluids to create a fluid mix. Below the esophagus 16, the (GI) tract expands to form the stomach 18. In the stomach 18 mechanical and chemical breakdowns of proteins occurs such that food leaves the stomach converted into a substance called chyme. From the stomach 18, the chyme, enters the small intestine 20 where secretions from the liver 22 and the pancreas 24 complete the digestive process.
The liver 22 produces which is then stored in the gall bladder 26. Bile is a complex mixture of essentially emulsifiers and surfactants that the body uses to absorb fat. Without bile, dietary fat is relatively insoluble and would pass out of the body as feces. The pancreas produces pancreatic enzymes which the body uses to digest and absorb proteins, and to a lesser degree, carbohydrates. Pancreatic enzymes move from the pancreas to the intestine through the pancreatic duct 28 which, in most individuals, combines with the bile duct 32 from the gall bladder 26 to form a common duct that enters the intestine through the Ampula of Vater 30 (also called the Ampulla of Vater, hepatopancreatic ampulla, ampulla biliaropancreatica). However, in some individuals, the bile duct 32 and pancreatic duct 28 remain separate and enter the small intestine 20 at separate location.
As the food fluid journeys through the small intestine 20, digested foodstuff, such as fats, are absorbed through the mucosal cells into both the capillary blood and the lacteal 38. Other digested foodstuffs, such as amino acids, simple sugars, water, and ions are absorbed by the hepatic portal vein 40. From the small intestine 20, the remainder of the food fluid enters the large intestine 42 whose major function is to dry out indigestible food residues and eliminate them from the body as feces 44 through the anal canal 46.
Current gastrointestinal tract surgeries require incisions to be made into the abdomen in order to attach the distal small intestine to the stomach and to make the stomach smaller. This procedure is sometimes called “Roux-en-Y” or gastro jejunal bypass with gastric reduction. The procedure is commonly performed through a large midline abdominal incision, although some surgeons have developed adequate skill to perform the procedure through a number of smaller incisions in a laparoscopic manner with cameras and instruments inserted through the holes for visualization. Both methods cause weight loss through bypass by reducing the effective length of intestine available for the absorption of food and the stomach is reduced in size so that the patient cannot eat a lot of food. However, both methods require anesthesia (usually general), a prolonged recovery time, and are not reversible once the target weight of the patient is reached.
Another procedure used is vertical stapled gastroplasty. This procedure involves incision of the anterior abdominal wall and creation of a 10-15 ml pouch from the proximal stomach by use of 4-6 rows of staples, with hundreds of staples in each row. This procedure also has numerous complications including rupture of the staple line, infection of the surgical incision, post operative hernias and the like. Moreover, due to the large amount of fat tissue in the anterior abdominal wall in the typical patient on whom this procedure is performed, poor healing of the operative wound may result. Furthermore prolonged post-operative bed rest after such extensive surgery predisposes obese patients to the development of deep vein thrombosis and possible pulmonary emboli, some with a potentially lethal outcome.